Such inwardly tensioning plain compression rings are for instance used in transmission technology as a gasket to seal a fixed flange in reference to a rotatable shaft for a pressure or lubrication oil supply to a hydraulic actuated clutch. The inwardly tensioning plain compression ring is hereby positioned usually in a circumferential groove which is designed into the flange or the shaft and the inwardly tensioning plain compression ring is mounted in this groove with axial and radial play so that the pressure and lubricant oil, through a pressure chamber or positive pressure region, can penetrate into the annular groove. In many cases, such an inwardly tensioning plain compression ring is slanted or partitioned, respectively, and is also designed springy so that it, in the case of an inwardly tensioning ring, attaches with its radial inner outside or circumferential surface, respectively, to a radial outer surface tensioning at one of the two parts and that it, in the case of an outer tensioning ring, attaches itself tensioning with its radial outer surface or circumferential surface, respectively, to a radial inner surface at one of the two designated parts. In the axial direction, the inwardly tensioning plain compression ring attaches itself, through the effect of the provided pressure liquid from the positive pressure region, at the side surface of the groove with an axial circumferential surface.
Depending on a desired configuration, either the radially attached circumferential surface, or the axially attached circumferential surface of the inwardly tensioning plain compression ring, rests opposite to either one of the parts. Accordingly, each of the radial circumferential surface or axial circumferential surface serves as a sealing sliding surface during relative rotation of both parts. To limit the thermal stress, which occurs at the respective sliding surface due to the created friction force, lubrication oil can be provided at the sliding surface for the removal of heat.
It is known to position at the sliding surface of a inwardly tensioning plain compression ring, distributed across its perimeter, several pocket shaped grooves for the accommodation of a lubricant, which are connected with a pressure chamber for the lubricant.
DE 39 04 978 C2 shows such a sealing ring which axially separates two chambers with different pressure levels, whereby the two chambers are limited through a shaft and a hub which accommodates it. The sealing ring is placed in an annular groove which is located at the shaft. The sealing ring is designed as an open and outward tensioning ring with an outer surface that radially attaches to and seals the wall of a hub bore and is fixed in reference to the hub bore. Axially, the sealing ring is attached at a side wall of the groove due to the higher pressure level in the area. Into the sliding sealing surface of the ring and over the perimeter, pocket shape grooves are positioned which are open against the larger pressure in this area.
It is also known to develop a continuous, ring shaped lubrication groove or indent, respectively, which is connected with the pressure chamber. Hereby and compared to segmented lubrication as in the case of lubrication pockets, a more effective, continuous lubrication film is created at the sliding surface. Through the application of pressure at the lubrication groove, the force of pressure at the sliding surface can also be reduced evenly across the perimeter, whereby the friction losses can be further reduced.
DE 10 56 440 A shows such an inwardly tensioning plain compression ring which is positioned outward tensioning in reference to a groove, which is designed in a shaft. The sealing ring has at both of its axial circumferential surfaces, which form a sliding surface, a continuous ring shape lubrication groove. The lubrication groove being acted on by pressure or lubrication liquid through radial supply ducts which are provided at the respective head surface of the ring.
Known from DE 21 46 026 C2 is an open, outward tensioning plain compression ring which is positioned between two parts which rotate relative to each other. The inwardly tensioning plain compression ring is positioned between a groove which is designed between these two parts, wherein at one of the axial sides a larger pressure is present as compared to the opposite side. The axial lower pressure side of the sealing ring is provided with a perimeter groove which can be applied with the lock sure pressure through ducts which run through the sealing ring. The sealing ring can also be provided at its radially outer circumferential surface with an annular groove, which can be applied with a larger pressure through ducts. A herewith comparable inwardly tensioning plain compression ring is also known from U.S. Pat. No. 3,315,968 A.
With a slotted inwardly tensioning plain compression ring, its two perimeter referenced opposite ends can form a simple, open ring with a joint gap. Already known are inwardly tensioning plain compression rings, for instance piston rings, where the two circumferentially opposite ends are designed as a lock. The ends of such rings, when self-springing of the rings is present, can be brought together or separated from each other by overcoming the self-springing of the rings.
DE 10 2009 012 462 A1 shows a rotary feed through with such a rectangular the ring which is positioned between a rotor and rotating part and the stator as the fixed part, whereby the stator surrounds the rotor. In accordance with an example embodiment, the inwardly tensioning plain compression ring is placed in the peripheral groove of the rotor. Through the application of pressure via an oil supply duct, the inwardly tensioning plain compression ring is pressed with its axial circumferential surface, with the side which is opposite to the oil supply duct, against the wall of the groove, and with its radial, outer circumferential surface attached to an inner surface of the stator. Due to the different dimensions of the cross section of the ring in height and width, the resulting surface forces are applied to the ring, which are different in the axial direction and the radial direction. Through a lesser width than height, an axially static sealing area in reference to the rotor is created, which fixes the inwardly tensioning plain compression ring in reference to this part, and creates also, in reference to the stator, a radially, outer, and dynamic sealing area enables the inwardly tensioning plain compression ring to slide in reference to this part. At least the dynamic sealing area is provided with at least one recess for the creation of a dedicated leakage for cooling and lubricating. The inwardly tensioning plain compression ring has a joint, or lock, which serves as a mounting aid. The recess is designed as a pocket and is located, in accordance with a variation in there, at the outer circumference of the inwardly tensioning plain compression ring as an integrated part in the construction of the joint or lock.